Method of producing electrophotographic photosensitive member, method of producing organic device, and emulsion for charge transporting layer

Abstract

Provided are a method of producing an electrophotographic photosensitive member, particularly, a method of producing an electrophotographic photosensitive member and an organic device by which, in a method of forming a charge transporting layer, the stability of an application liquid for the layer after long-term storage is improved while the usage of an organic solvent in the application liquid is curtailed, and the layer having high uniformity is formed. The method is a method of producing an electrophotographic photosensitive member which includes a support and a charge transporting layer formed thereon, the method including: preparing a solution including: a first liquid whose solubility in water under 25° C. and 1 atmosphere is 1.0 mass % or less; a second liquid whose solubility in water under 25° C. and 1 atmosphere is 5.0 mass % or more; a charge transporting substance; and a binder resin; preparing an emulsion by dispersing the solution in water; forming a coat for the layer on the support by using the emulsion; and forming the layer by heating of the coat.

The invention claimed is: 
     
       1. A method of producing an electrophotographic photosensitive member which comprises a support and a charge transporting layer formed thereon, the method comprising the steps of:
 preparing a solution comprising (i) a first liquid whose solubility in water under 25° C. and 1 atmosphere is 1.0 mass % or less, (ii) a second liquid whose solubility in water under 25° C. and 1 atmosphere is 5.0 mass % or more, (iii) a charge transporting substance, and (iv) a binder resin; 
 preparing an emulsion by dispersing the solution in water; 
 forming a coat for the charge transporting layer by using the emulsion; and 
 forming the charge transporting layer by heating the coat. 
 
     
     
       2. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein the second liquid comprises at least one selected from the group consisting of tetrahydrofuran, dimethoxymethane, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 1,3,5-trioxane, methanol, 2-pentanone, ethanol, tetrahydropyran, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, propylene glycol n-butyl ether, propylene glycol monopropyl ether, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monoallyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, methyl acetate, ethyl acetate, n-propyl alcohol, 3-methoxybutanol, 3-methoxybutyl acetate, and ethylene glycol monomethyl ether acetate. 
     
     
       3. The method of producing the electrophotographic photosensitive member according to  claim 2 , wherein the binder resin is soluble in the first liquid. 
     
     
       4. The method of producing the electrophotographic photosensitive member according to  claim 3 , wherein the second liquid is a liquid whose solubility in water under 25° C. and 1 atmosphere is 20.0 mass % or more. 
     
     
       5. The method of producing the electrophotographic photosensitive member according to  claim 3 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       6. The method of producing the electrophotographic photosensitive member according to  claim 2 , wherein the second liquid is a liquid whose solubility in water under 25° C. and 1 atmosphere is 20.0 mass % or more. 
     
     
       7. The method of producing the electrophotographic photosensitive member according to  claim 6 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       8. The method of producing the electrophotographic photosensitive member according to  claim 2 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       9. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein the binder resin is soluble in the first liquid. 
     
     
       10. The method of producing the electrophotographic photosensitive member according to  claim 9 , wherein the second liquid is a liquid whose solubility in water under 25° C. and 1 atmosphere is 20.0 mass % or more. 
     
     
       11. The method of producing the electrophotographic photosensitive member according to  claim 10 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       12. The method of producing the electrophotographic photosensitive member according to  claim 9 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       13. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein the second liquid is a liquid whose solubility in water under 25° C. and 1 atmosphere is 20.0 mass % or more. 
     
     
       14. The method of producing the electrophotographic photosensitive member according to  claim 13 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       15. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein a ratio (w/(a+b+r+ct)) in the emulsion is 5/5 to 7/3,
 where “w” represents the mass of the water in the emulsion, “a” represents the mass of the first liquid in the emulsion, “b” represents the mass of the second liquid in the emulsion, “ct” represents the mass of the charge transporting substance in the emulsion, and “r” represents the mass of the binder resin in the emulsion. 
 
     
     
       16. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein a ratio (a/b) of the mass of the first liquid (a) to the mass of the second liquid (b) in the emulsion is 1/9 to 9/1. 
     
     
       17. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein the first liquid is at least one liquid selected from the group consisting of toluene and xylene. 
     
     
       18. The method of producing the electrophotographic photosensitive member according to  claim 1 , wherein the second liquid is at least one liquid selected from the group consisting of tetrahydrofuran and dimethoxymethane. 
     
     
       19. A method of producing an organic device comprising a charge transporting layer, the method comprising the steps of:
 preparing a solution comprises (i) a first liquid whose solubility in water under 25° C. and 1 atmosphere is 1.0 mass % or less, (ii) a second liquid whose solubility in water under 25° C. and 1 atmosphere is 5.0 mass % or more, (iii) a charge transporting substance, and (iv) a binder resin; 
 preparing an emulsion by dispersing the solution in water; 
 forming a coat for the charge transporting layer by using the emulsion; and 
 forming the charge transporting layer by heating the coat. 
 
     
     
       20. The method of producing the organic device according to  claim 19 , wherein the second liquid comprises at least one selected from the group consisting of tetrahydrofuran, dimethoxymethane, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 1,3,5-trioxane, methanol, 2-pentanone, ethanol, tetrahydropyran, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, propylene glycol n-butyl ether, propylene glycol monopropyl ether, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monoallyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, methyl acetate, ethyl acetate, n-propyl alcohol, 3-methoxybutanol, 3-methoxybutyl acetate, and ethylene glycol monomethyl ether acetate.